Rotors of many types of rotational machinery need to be balanced to ensure smooth operation and longevity. For example, turbine and compressor rotors of gas turbines and impellers of pumps require balancing to correct any unbalance as part of initial manufacturing and often in connection with periodic maintenance. These rotors can span a broad range of sizes and weights, and those that are very large, for example, weighing hundreds to thousands of pounds, can make balance testing and balance correction challenging, time consuming and expensive.